JP4053687B2 - Rubber extrusion equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention is suitable, for example, for extrusion molding of tread rubber for tire molding, and uses a plurality of rubber extruders to form a rubber extruded body having a partition wall-like cross-sectional area extending in the thickness direction. Relates to the device.
[0002]
[Prior art]
In the tire, since the required characteristics in each part are different, the tire is constituted by a plurality of types of rubber members having different compositions. For example, in the tread rubber TA, generally, as shown in FIG. 9A, a cap rubber G1 having a tread surface and excellent cut resistance and wear resistance, and a low loss disposed on the carcass side of the cap rubber G1. It is often constituted by a base rubber G2 having a coefficient (tan δ) and a cross-sectional area from the win rubber G3 that covers both side surfaces of the tread and has excellent adhesion to the side wall rubber.
[0003]
Such a tread rubber TA is usually formed by connecting rubber extruders m1 to m3 for discharging the rubbers G1 to G3 to an extrusion head b having a preformer a as shown in FIG. 9B. Using the device c, a belt-like rubber extruded body w is extruded from a die d. At this time, each of the rubber extruders m1 to m3 is attached to a non-extruded side surface s2 other than the extruded side surface s1 on which the die d is arranged due to the configuration of the rubber flow path. Further, a thin cushion rubber G5 having excellent adhesion to a belt layer or the like is usually attached to the carcass side of the rubber extruded body w after being extruded.
[0004]
On the other hand, in the tire, it has been proposed to use silica as a main reinforcing agent for the cap rubber rubber G1 from the viewpoint of further energy saving. Unlike carbon black, silica is chemically bonded to rubber via a binder, and thus has an advantage that wet performance can be improved while reducing rolling resistance, such as rich adhesiveness. On the other hand, since silica has high electrical insulation, this silica compound tire has a large electrical resistance, and has a drawback that static electricity tends to accumulate in the vehicle without being grounded. Note that the base rubber G2 itself has a low loss coefficient (tan δ), so the amount of carbon black is small, and good conductivity cannot be expected.
[0005]
Therefore, in recent years, as shown in FIG. 8A, as the tread rubber TB, there is one partition wall-like conductive terminal rubber G4 made of conductive rubber and extending through both the cap rubber G1 and the base rubber G2. The structure provided above has been proposed.
[0006]
[Problems to be solved by the invention]
However, in order to extrude the tread rubber TB having the above structure, as shown by a one-dot chain line in FIG. 9B, the surface s2 on the non-extrusion side of the extrusion head b, particularly below the rubber extruder m3. While the rubber extruder m4 for the rubber G4 is connected to the empty space, the body of the extrusion head b, the base former h, and the preformer a, each of which forms the rubber flow path e of the rubber G4, are newly produced and mounted. It is necessary to do. As a result, the change of the apparatus becomes large and the equipment cost increases greatly.
[0007]
Further, the conductive terminal rubber G4 is discharged from the tread surface side of the tread rubber TB, but the discharge pressure decreases toward the downstream side. Therefore, as shown in FIG. 8B, the conductive terminal rubber G4 is tapered toward the carcass side. In some cases, the conductive terminal rubber G4 is not penetrated in the base rubber G2 as shown by a one-dot chain line. May cause poor conduction. At this time, since the base rubber G2 is covered with the cushion rubber G5, it is difficult to easily confirm the presence or absence of this interruption visually, and there is a problem that the subsequent inspection work is complicated. .
[0008]
Accordingly, the present invention has been made paying attention to the fact that a secondary rubber extruder with a small extrusion capacity can be used as the rubber extruder m4, and this secondary rubber extruder is used as a surface on the extrusion side of the extrusion head. In addition to providing a guide member with a groove-like flow path that forms partition wall-like conductive terminal rubber (cross-sectional area) on the upstream side of the die, the change to the conventional extrusion head is minimized The purpose is to provide a rubber extrusion device that can reduce the cost and keep the increase in cost low, and can visually determine the presence or absence of breakage of the conductive terminal rubber, making the inspection work simple, highly accurate and reliable and efficient. It is said.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, the invention of claim 1 of the present application is directed to an extrusion side of a rubber extruded body having a plurality of rubber extruders and a plurality of cross-sectional areas formed by rubber discharged from the rubber extruder. A rubber extrusion apparatus including an extrusion head for extruding from a die provided on the surface of
The rubber extruder includes a main rubber extruder connected to a surface other than the extrusion side surface of an extrusion head, and a secondary rubber extruder connected to the extrusion side surface,
In addition, the extrusion head has a rubber preform formed by rubber discharged from the main rubber extruder, and a partition wall-like cross-sectional area dividing the rubber preform in the sheet width direction. A guide member having a groove-like channel formed by rubber discharged from an extruder is provided on the upstream side of the die.
[0010]
According to a second aspect of the present invention, the extrusion head includes a preformer that forms the rubber preform from rubber discharged from the main rubber extruder, and the guide member has a distance from the preformer. The guide member is spaced apart and interposed between the dies, and the guide member has a small plate shape that crosses the rubber flow path through which the rubber preform flows in a range in which the partition wall-shaped cross-sectional area is formed, Moreover, the groove-like flow path is characterized by opening toward the downstream side.
[0011]
According to a third aspect of the present invention, the auxiliary rubber extruder is detachable from the extrusion head and can be moved away from the extrusion head.
[0012]
According to a fourth aspect of the present invention, the rubber extruded body is a tread rubber for molding a tire, and the rubber pre-formed body is a cap rubber that forms a tread surface and is made of a non-conductive rubber, and the tire rubber side of the cap rubber. The base rubber extending in the width direction and the wing rubber covering both side surfaces of the tread are formed with at least the cap rubber, and the rubber in the partition wall-shaped cross-sectional area is made of conductive rubber. Yes.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a conceptual diagram showing a rubber extrusion device 1 according to the present invention. The rubber extrusion device 1 is formed by a plurality of rubber extruders M and a plurality of rubbers G discharged from the rubber extruders M. And an extrusion head 3 that extrudes a rubber extruded body W having a cross-sectional area R from a die 2 provided on an extrusion-side surface S1.
[0014]
Here, in this example, the case where the rubber extruded body W is a tread rubber TB for tire molding is illustrated as shown in FIG. 8A, and the tread rubber TB is as described above. , Cap rubber G1, base rubber G2, wing rubber G3, and conductive terminal rubber G4. And these rubber | gum G1-G4 forms several cross-sectional area | region R1-R4 in the rubber extruded body W. As shown in FIG.
[0015]
After the extrusion molding, a cushion rubber G5 extending in the width direction by, for example, roll molding is attached to the carcass side of the tread rubber TB. In this example, the cap rubber G1 is made of non-conductive rubber containing silica, and the base rubber G2 is made of non-conductive rubber having a low loss coefficient (tan δ) by reducing the amount of carbon black. Further, the wing rubber G3, the conductive terminal rubber G4, and the cushion rubber G5 are each formed of a conductive rubber containing normal carbon black.
[0016]
Next, the rubber extruder M is connected to a surface S2 other than the extrusion side surface S1 of the extrusion head 3 (hereinafter referred to as a non-extrusion side surface S2) and discharges the rubbers G1 to G3. M1-M3, and a secondary rubber extruder M4 connected to the extrusion-side surface S1 and discharging the rubber G4.
[0017]
The extrusion head 3 is pre-formed with rubber G1 to G3 discharged from the main rubber extruders M1 to M3 to a head body 3A for fixing the discharge ports 4 of the main rubber extruders M1 to M3. A preformer 5 for forming a body W1, a guide member 6 for forming the partition wall-shaped sectional area R4 of rubber G4 in the rubber preform W1, and the die 2 having a molding port 2A having a final sectional shape. It is installed.
[0018]
Reference numerals 7A to 7C in FIG. 1 are guide passages for guiding the rubbers G1 to G3 from the main rubber extruders M1 to M3 to the preformer 5, respectively. This is a base former 9 for integrally connecting the guide member 6 and the die 2.
[0019]
As shown in FIG. 2, the preformer 5 includes inlets 10 </ b> A to 10 </ b> C into which rubbers G <b> 1 to G <b> 3 passing through the guide channels 7 </ b> A to 7 </ b> C individually flow, and rubbers G <b> 1 to G <b> 3 from the inlets 10 </ b> A to 10 </ b> C. Are individually divided into the cross-sectional areas R1 to R3, and the individual flow paths 11A to 11C for merging with one rubber preform W1, and the outlets where the individual flow paths 11A to 11C merge and open. And twelve. 5A and 5B schematically show the state of the cross-sectional shape of the rubber at the inlets 10A to 10C and the outlet 12, and the rubber preform W1 is formed by the merging at the outlet 12. Is formed.
[0020]
The base former 9 is provided with a rubber flow path 13 for guiding the rubber preform W1 from the outlet 12 to the molding port 2A of the die 2. In this example, the rubber flow path 13 is composed of parallel holes whose cross-sectional shape is substantially the same as that of the outflow port 12, thereby smoothing the rubber flow and stably maintaining the boundary line between the cross-sectional areas R1 to R3. To do.
[0021]
2 and 3, in this example, the die 2 is formed in a recess 9A on the lower surface of the base former 9 (hereinafter, the upstream surface may be referred to as the upper surface and the downstream surface as the lower surface for convenience). A flat plate-like substrate 15 to be fitted is provided, and the molding port 2 </ b> A is formed through the substrate 15. The lower surface of the substrate 15 constitutes a part of the extrusion-side surface S1, and in this example, a connection portion 16 is provided on the lower surface of the substrate 15 for detachably connecting the auxiliary rubber extruder M4. ing.
[0022]
In this example, the connecting portion 16 includes a spherical seat 16A that is recessed in a spherical shape on the lower surface, and a conduction hole 16B that penetrates the substrate 15 at the center of the spherical seat 16A. Is formed on the carcass side of the tread rubber TB with respect to the molding port 2A, that is, on the right side of the molding port 2A in FIG.
[0023]
The main and sub rubber extruders M1 to M4 have a known configuration in which the rubber G introduced from the hopper is kneaded and melted by the rotation of the screw shaft. In this application, the sub rubber extruder M4 is the main rubber extruder M4. Smaller ones having a smaller extrusion capacity than the rubber extruders M1 to M3 are used.
[0024]
In this example, the secondary rubber extruder M4 includes a cylinder 17 that stands upright with the discharge end 17A facing the die 2, and the discharge end 17A has a curved surface equal to the spherical seat 16A. A spherical head 19 that can engage with the spherical seat 16A is formed. Further, as shown in FIG. 1, the auxiliary rubber extruder M4 is disposed on a traveling base 21 that travels on the rail 20 via an advancing / retreating means 22 that is, for example, a cylinder. The advance / retreat means 22 can bias the spherical head 19 to the spherical seat 16A.
[0025]
Therefore, the spherical head 19 can be pressed against the spherical seat 16A and the auxiliary rubber extruder M4 can be connected to the extrusion head 3 with one touch by forward movement (in this example, ascending) by the advance / retreat means 22. On the contrary, it can be removed from the extrusion head 3 with one touch by the backward movement of the advance / retreat means 22 (down in this example). Moreover, the traveling table 21 can move away from the extrusion head 3 in a direction different from the forward / backward movement. It should be noted that the combination of the spherical seat 16A and the spherical head 19 has the advantage that high-precision positioning at the time of connection becomes unnecessary.
[0026]
Next, as shown in FIGS. 2 to 4, the guide member 6 has a narrow plate shape that crosses the rubber flow path 13 within a range in which the partition wall-shaped cross-sectional area R <b> 4 is formed. Overlaid on top.
[0027]
The guide member 6 includes a partition wall portion 23 that divides the rubber preform W1 into a plurality of divided bodies Wa in the sheet width direction F by crossing the rubber flow path 13. That is, in this example, the guide member 6 includes the partition wall 23 and a hole 24 that is disposed between the partition walls 23 and 23 and forms a divided portion of the rubber flow path 13.
[0028]
Further, the guide member 6 has a concave groove portion 25 formed in the lower surface thereof. The concave groove portion 25 communicates with the conduction hole 16B of the die 2 so as to accommodate the rubber G4 from the auxiliary rubber extruder M4, and a groove-like flow path 25B branched from the storage portion 25A. With.
[0029]
The groove-like channel 25B is a narrow narrow groove that passes through the partition wall 23, and forms an opening 26 that opens toward the downstream side only at a portion that crosses the molding hole 2A. The other part of the groove 25 is sealed by the upper surface of the die 2, and therefore the groove 25 forms a flow path through which the rubber G4 flows from the conduction hole 16B toward the opening 26. .
[0030]
Accordingly, the rubber preform W1 passing through the rubber flow path 13 is once divided into a plurality of divided bodies Wa by the partition wall portion 23 of the guide member 6 as conceptually shown in FIGS. 6 (A) to (C). Is done. Then, in each space 29 between the divided bodies Wa, the rubber G4 from the groove-like channel 25B is jetted toward the downstream side. In this example, the rubber G4 is integrated with each divided body Wa in the die 2, and a rubber molded body W having a partition wall-shaped cross-sectional area R4 is extruded.
[0031]
As described above, in the rubber extrusion device 1, by using the guide member 6, a space for mounting the guide portion 6 material is provided in the base former 9 and the connecting portion 16 is formed in the die 2. The change to the conventional extrusion head, such as being able to form the molded body W, can be minimized, and the increase in equipment cost can be greatly suppressed.
[0032]
Moreover, since the connecting portion 16 can be freely formed on the carcass side (right side in the drawing) of the molding port 2A, the rubber G4 can flow from the carcass side of the tread rubber TB toward the tread surface. As a result, the interruption of the rubber G4 due to the flow failure can be easily confirmed by visual observation on the tread surface, and the conduction failure with the cushion rubber G5 can be surely prevented, and the subsequent complicated conduction test is eliminated. Is also possible.
[0033]
Further, in the rubber extruding device 1, a tread rubber TA (shown in FIG. 9A) without the conductive terminal rubber G4 can be formed from the same extruding head 3 simply by removing the auxiliary rubber extruding machine M4. That is, the production line can be easily switched when producing the two types of tread rubbers TA and TB, and the production efficiency can be improved. Further, the conventional workability for the tread rubber TA can be ensured by retracting the removed secondary rubber extruder M4 to a place away from the extrusion head 3 using the traveling table 21 or the like.
[0034]
Also, the combination of the spherical seat 16A and the spherical head 19 makes it possible to simplify the attaching / detaching operation of the auxiliary rubber extruder M4 with one touch, and to improve the maintenance such as cleaning.
[0035]
In this example, the secondary rubber extruder M4 is connected to the lower surface of the die 2, but may be configured to be connected to the lower surface of the base former 9. As the tread rubber TB, as shown in FIGS. 7A to 7C, a structure having at least the cap rubber G1 among the cap rubber G1, the base rubber G2, and the wing rubber G3 can be adopted. Further, the cushion rubber G5 may be eliminated. In such a case, the conductive terminal rubber G4 can be brought into direct contact with the belt layer or the like.
[0036]
Moreover, the rubber extrusion apparatus 1 of this application is employable for formation of the various rubber extrusion body which has a some cross-sectional area, without being limited to a tread rubber.
[0037]
【The invention's effect】
Since the present invention is configured as described above, a partition wall-like cross-sectional area is easily formed in a rubber molded body while minimizing changes to the conventional extrusion head and keeping the increase in equipment cost low. be able to. In addition, it is possible to form a rubber molded body that can easily confirm visually whether there is a break in the sectional area of the partition wall shape.
[Brief description of the drawings]
FIG. 1 is a conceptual diagram of an apparatus according to an embodiment of the present invention.
FIG. 2 is an enlarged cross-sectional view showing the main part of the extrusion head.
FIG. 3 is a perspective view showing a guide member.
FIG. 4 is a cross-sectional view thereof.
5A and 5B are conceptual diagrams showing the state of the cross-sectional shape of the rubber at the cross-sectional positions I and II in FIG.
FIGS. 6A to 6C are conceptual diagrams illustrating states of a cross-sectional shape of rubber showing a process in which a partition wall-shaped cross-sectional region is formed.
FIG. 7 is a cross-sectional view showing another example of tread rubber.
8A is a cross-sectional view of an example of a rubber molded body formed by the apparatus of the present application, and FIG. 8B is an enlarged cross-sectional view illustrating one of the conventional problems.
9A is a cross-sectional view showing an example of a tread rubber, and FIG. 9B is a conceptual diagram of a conventional apparatus for extruding it.
[Explanation of symbols]
2 Die 3 Extrusion head 5 Preformer 6 Guide member 13 Rubber flow path 25B Groove flow path F Sheet width direction G Rubber G1 to G3 Rubber G4 discharged from the main rubber extruder Rubber discharged from the secondary rubber extruder M Rubber Extruder M1 to M3 Main Rubber Extruder M4 Secondary Rubber Extruder R Cross Section Area R4 Partition Wall Cross Section Area S1 Extrusion Side Surface S2 Surface Excluding Extrusion Side Surface W Rubber Extrusion W1 Rubber Preformed Body

Claims (4)

A rubber extrusion apparatus comprising a plurality of rubber extruders and an extrusion head for extruding a rubber extruded body having a plurality of cross-sectional areas formed by rubber discharged from the rubber extruder from a die provided on an extrusion side surface Because
The rubber extruder includes a main rubber extruder connected to a surface other than the extrusion side surface of an extrusion head, and a secondary rubber extruder connected to the extrusion side surface,
In addition, the extrusion head has a rubber preform formed by rubber discharged from the main rubber extruder, and a partition wall-like cross-sectional area dividing the rubber preform in the sheet width direction. A rubber extruding apparatus characterized in that a guide member having a groove-like channel formed by rubber discharged from an extruder is provided on the upstream side of the die. The extrusion head includes a preformer that forms the rubber preform by rubber discharged from the main rubber extruder, and the guide member is spaced from the preformer and between the die. And the guide member has a narrow plate shape that crosses the rubber flow path through which the rubber pre-formed body flows so as to form the partition wall-shaped cross-sectional area, and the groove-shaped flow path is downstream. 2. The rubber extruding device according to claim 1, wherein the rubber extruding device opens toward the side. 3. The rubber extruding apparatus according to claim 1, wherein the auxiliary rubber extruding machine is detachable from the extruding head and can be moved away from the extruding head. The rubber extruded body is a tread rubber for molding a tire, and the rubber preform is a cap rubber made of a non-conductive rubber that forms a tread surface, a base rubber extending in a width direction on the tire carcass side of the cap rubber, The wing rubber covering both side surfaces of the tread is formed with at least the cap rubber, and the rubber in the cross-sectional area of the partition wall is made of conductive rubber. A rubber extruding device according to claim 1.

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